I began with myself. I started to sing and play long tones, and to listen and observe how these tones affected me mentally and physically. I noticed that I could change my emotional state by concentrating my attention on a tone. I noticed that I could feel my body responding with relaxation or tension. Prolonged practice brought about a heightened state of awareness that gave me a sense of well-being.

Pauline Oliveros, Deep Listening, loc. 47